A. Antreasyan

GexSi1−x strained‐layer heterostructure bipolar transistors

Double heterostructure bipolar transistors with the base region consisting of a p‐Ge0.5Si0.5 strained‐layer superlattice have been grown by molecular beam epitaxy. At a wavelength of 1.3 μm, optical gain as high as 52 has been achieved in two‐terminal phototransistors. The large photocurrent is inferred to be a product of the transistor gain, on the order of 20, and avalanche multiplication. A differential current gain of 10 has been obtained in the three‐terminal bipolar transistors. The incorporation of a narrow band‐gap GexSi1−x superlattice base is expected to result in higher emitter injection efficiency as compared to Si bipolar transistors.

Ge0.6Si0.4 rib waveguide avalanche photodetectors for 1.3 μm operation

Performance of strained‐layer superlattice Ge0.6Si0.4 waveguide avalanche photodetectors is evaluated for optical fiber applications at 1.3 μm. These devices are grown on Si substrates by molecular beam epitaxy. Waveguiding is accomplished by means of a 1.5–1.8‐μm‐thick Si rib waveguide which provides an effective index step of δn=8×10−3. The detector response bandwidth exceeds 8 GHz at a gain of 6. A receiver sensitivity of ηP=−29.4 dBm has been obtained at the data rate of 800 Mb/s with the corresponding error‐free transmission over 45 km of single mode fiber.

Ga0.47In0.53As ultrahigh gain, high sensitivity photoconductors grown by chloride vapor‐phase epitaxy

We report highly sensitive planar, interdigitated Ga0.47In0.54As photoconductive detectors prepared by trichloride vapor‐phase epitaxy. The devices exhibit dc gains as high as 104 at 1.3 μm. For a bit rate of 500 Mbit/s a sensitivity of P=−35.4 dBm has been measured at 1.55 μm. With devices having unity gain quantum efficiencies of η=33% we obtain ηP=−40 dBm matching the highest sensitivity measured with a p‐i‐n photodetector at similar bit rates. The devices show responsivities in excess of 3000 A/W and detectivities ranging between 1012 and 1013 cm Hz1/2 W−1. These values represent the highest performance that has ever been achieved with photoconductors in this wavelength range.

Electro‐optic sampling measurements of high‐speed InP integrated circuits

Multigigahertz waveforms in an InGaAs/InP metal‐insulator‐semiconductor field‐effect transistor inverter circuit have been measured noninvasively using the electro‐optic sampling technique with pulses from a gain‐switched InGaAsP laser. Propagation delays as low as 15 ps in a single inverter stage have been measured.

High‐speed operation of InP metal‐insulator‐semiconductor field‐effect transistors grown by chloride vapor phase epitaxy

We report the millimeter‐wave performance of enhancement mode InP metal‐insulator‐semiconductor field‐effect transistors grown by chloride vapor phase epitaxy. For a gate length of 1 μm we have measured a current gain cutoff frequency of 29 GHz and an electron velocity of 2.5×107 cm/s, close to a theoretical current gain cutoff frequency of 40 GHz. This represents the fastest InP‐based field‐effect transistor ever demonstrated, and surpasses state‐of‐the‐art AlGaAs/GaAs modulation‐doped field‐effect transistors having similar gate length.

High-speed enhancement-mode InP MISFET's grown by chloride vapor-phase epitaxy

We report the properties of enhancement mode InP metal-insulator-semiconductor field-effect transistors fabricated on semi-insulating InP substrates. The epitaxial layers of the device structure have been grown by chloride vapor phase epitaxy. Short-circuit current gain cut-off frequencies of 29 GHz were measured for 1 µm gate length devices, close to a theoretical value of 40 GHz. For devices having submicron gate lengths extrinsic transconductance values up to 300 mS/mm were measured. We have successfully utilized SiO2deposited by electron beam evaporation, and plasma enhanced CVD Si3N4as gate insulators, with a drain current drift of 30 percent within the first 50 hours of operation. The high-speed performance of the MISFETs represent to our knowledge the fastest InP-based field-effect transistor ever demonstrated, and surpasses that of the state-of-the-art AlGaAs/GaAs modulation doped field-effect transistors having similar gate length.

High‐speed enhancement mode InP metal‐insulator‐semiconductor field‐effect transistors exhibiting very high transconductance

We report the fabrication and performance of enhancement mode InP metal‐insulator‐semiconductor field‐effect transistors having transconductances as high as 200 mS/mm for a gate length of 1 μm. The epitaxial layers of the structure have been grown by chloride vapor phase epitaxy. Electron beam evaporated SiO2 has been utilized as gate insulator. The metal‐insulator‐semiconductor field‐effect transistors have low gate to source leakage currents (<125 nA) and saturation drift velocities as high as 3×107 cm/s. The transconductance value achieved in the present work is the highest ever measured on InP field‐effect transistors.

High performance Ga0.47In0.53As photoconductive detectors grown by chemical beam epitaxy

We have fabricated highly sensitive, planar, interdigitated photoconductive detectors on undoped Ga0.47In0.53As that is grown lattice matched on a semi‐insulating InP substrate by chemical beam epitaxy. The devices exhibit intensity‐dependent gains as high as 7000, gain‐bandwidth products of 20 GHz, detectivities as large as 1012 cm Hz1/2 W−1 at 300 K, and responsivities close to 3000 A/W at λ=1.3 μm. These results are similar to the highest performance characteristics obtained with Ga0.47In0.53As photoconductive detectors that are grown by well established techniques.

Stop-cleaved InGaAsP lasers for monolithic optoelectronic integration

We report a novel technique for locally cleaving the mirrors of semiconductor lasers without cleaving the entire substrate. The stop‐cleaving technique involves the etching of holes on a substrate prior to the conventional cleaving procedure. The presence of the hole prevents the propagation of the cleavage plane along the entire substrate. The technique permits the fabrication of lasers with cleaved mirrors without imposing any limitation on the size of the substrate; thus, it is suitable for monolithic optoelectronic integration. InGaAsP lasers (λ=1.3 μm) with stop‐cleaved mirrors have been fabricated and have threshold currents comparable to those with conventionally cleaved mirrors.

Monolithic InGaAs p‐i‐n InP metal‐insulator‐semiconductor field‐effect transistor receiver for long‐wavelength optical communications

We have fabricated a monolithically integrated p‐i‐n field‐effect transistor (FET) receiver consisting of an InGaAs/InP p‐i‐n detector and a high‐speed InP metal‐insulator‐semiconductor field‐effect transistor. The receiver sensitivity of the p‐i‐n FET is −18.2 dBm at a bit rate of 2.4 Gb/s and a wavelength of 1.55 μm.